Many wellbore operations utilise injection systems which facilitate injection of fluids into wellbore regions. Such injection may be utilised for treating purposes, such as to treat specific regions of a subterranean formation, for example to improve permeability of the geology. Further, such injection may be utilised as a means of assisting the recovery of fluids to surface, for example by modifying the viscosity or effective density of the produced fluid or the like.
Known injection systems may include an injection conduit, sometimes referred to as a capillary conduit, which extends through a wellbore to the required depth. One or more valves are typically included within the system, coupled to the injection conduit, wherein the valves function to check any reverse flow through the conduit back to surface. The injection system is typically suspended within the wellbore via a tubing hanger. However, in some cases if a valve ever needs to be recovered it may be necessary to recover the entire injection conduit, which in some applications might extend for thousands of meters, thus involving a complex and time consuming process.
It has been proposed in the prior art to provide a subsurface safety valve (SSSV) which is operated by fluid pressure applied through an associated wellbore injection system. For example, US 2006/0021750 discloses an injection system which includes a surface controlled subsurface safety valve which incorporates an injection valve, with an injection line suspended directly from the safety valve. The arrangement disclosed in US 2006/0021750 is such that as the injection line is suspended directly from the safety valve, in the event of recovery of the safety valve, for example to replace the injection valve, the injection line would also need to be recovered.
EP 2481882 discloses a subsurface safety valve which incorporates injection capabilities for injecting an additive into a wellbore.